Pulp molding apparatus



H. A. WOLTER PULP MOLDING APPARATUS 3 Sheets-Sheet 1 Locu ATTORNEY Nov.22, 1960 Filed may 10, 1957 Nov. 22, 1960 H. A. woLTER PULP MOLDINGAPPARATUS 3 Sheets-SheeiI 2 Filed May l0, 1957 INVENTOR am LocusATTORNEY NOV. 22, 1950 H. A. woLTER 2,961,042

PULP MOLDING APPARATUS Filed May l0, 1957 3 Sheets-Sheet 3 INVENTOR@Q2/@ym ATTORNEY Unite States atent O PULP MLDNG APPARATUS Harry A.Wolter, Ain-on, Ohio, assignor to Diamond National Corporation, acorporation of Delaware Filed May 10, 1957, Ser. No. 658,410

8 Claims. (Cl. 162-394) This invention relates to pulp moldingapparatus, and more particularly to an improvement in apparatus forsuccessively molding pulp articles.

In the manufacture of molded pulp articles by the usual process ofsuction molding the articles from a Water slurry of pulp fibers, it hasbeen customary to employ a rotary carrier having a plurality offoraminous forming dies mounted on its periphery, which dies aresubjected to suction internally as they are advanced successivelythrough a vat containing the slurry during rotation of the carrier. Thisaction causes layers of wet pulp bers to be extracted from the slurryand deposited on the molds, thereby forming initially molded articles,known as preforms. In order to extract some of the excess moisture fromthe wet pulp preforms, the suction applied to the molds is continued asthe molds emerge from the slurry and advance successively `upwardthereabove during continued rotation of the mold carrier. At apredetermined point above the slurry, a transfer device, which isusually of the rotary type also, suc- Iessively removes the preformsfrom the molds and transfers them to a dryer.

The above-described rotary type multiple die molding apparatus isparticularly suitable for high speed production of large quantities ofrelatively non-complex, small, low unit cost molded pulp products, suchas pie plates and egg cartons. However, the high initial costs requiredfor purchase and installation of this equipment represent such a largeinvestment to be amortized, that only such large. quantity productionitems can be manu- `factured economically. One of the principal reasonsfor this situation is the high cost of the individual molding dies. Inorder to provide for the manufacture of smaller quantities and specialorders for items requiring larger or more complex molding dies, a needhas existed for less expensive apparatus combining simplicity withefficiency, and preferably this apparatus should have only a singlecooperating pair of dies. Although apparatus of this general type hasbeen known in the past, none of the prior art apparatus has beenentirely satisfactory.

An object of this invention is to provide new and improved pulp moldingapparatus.

Another object of the invention is to provide a more eiiicient,simplified, and inexpensive pulp molding ,apparatus of the typeembodying only a single p air of cooperating dies.

Still another object of the invention is to provide a new and improvedmechanical movement for a single pair of cooperating dies in a pulpmolding machine.

Other objects and the nature and advantages of the instant inventionwill be apparent from the following description, taken in conjunctionwith the accompanying drawings, wherein:

Fig. l is a fragmentary side elevation view of pulp molding apparatusembodying the invention, shown in one operating position of a moldingoperation;

Fig. 2 is a corresponding view of the apparatus illustrated in Fig. l,but showing the apparatus in another operating position;

Fig. 3 is a fragmentary side elevation view of pulp molding apparatusforming a second embodiment of the invention, shown in one operatingposition of a molding operation; t

Fig. 4 is a view corresponding with that of Fig. 3, but showing theapparatus in another operating position; and

Fig. 5 is a plan view of the apparatus corresponding with Fig. 3.

Molding apparatus embodying the invention features a simplied structuralorganization and an improved type of simple mechanical movement, incomparison with that of the complex machines generally employedlheretofore. In the embodiment of the invention illus,- trated in Figs.1 and 2, a molding die 19 having a forarninous forming face 11 isvertically reciprocable into and out of a vat 12 containing pulp slurry.The die 19 is secured to the lower end of a hollow vertical shaft 14,which is connected to a source of suction (not shown) for the purpose ofapplying suction to the interior of the die 1t) during its immersion inthe pulp slurry contained in the vat 12. Any suitable means may beemployed for imparting vertical reciprocatory motion to the shaft 14,and such means is so well known that it is considered unnecessary toillustrate and describe it in detail. The resultant reciprocatory motionimparted to the die 10 moves it alternately between a molding positionimmersed in the pulp slurry, shown in Fig. 1, and a Vcompressingposition elevated above the slurry, depicted in Fig. 2.

A particularly important feature of the invention is the fact that themotion of the die 16 is perfectly linear, being reciprocated in astraight line between its immersed position and its elevated position.Another important feature of the invention is the fact that the die 1t)is held facing its immersed position at all times, without Ytilting orturning during its reciprocatory motion. Thus, the forming face 11 ofthe die 1i) is always disposed horizontally and facing downwardly,although some slight deviation may be permissible. This arrangementinsures a uniform depth of deposition of the pulp fibers from the slurryon all portions of the forming face of the molding die, and makes itpossible to mold deep articles with greater success than was heretoforepossible. If a molding die were moved into theslurry with an arcuatemovement, or if the die entered sideways, a washing eiect wouldinevitably occur on certain portions of the die, thereby resulting in alack of uniformity in the deposition of pulp fibers thereon. Thisundesirable effect is completely avoided in apparatus em bodying theinvention by having the molding die enter the slurry in a straight linemovement While facing its ultimate immersed position.

When the molding die 10 is in its elevated position, it is brought intoregistration with a cooperating compression and transfer die 16 having aforaminous forming face 17 designed to mate with the forming face 11 ofthe die 10. The die 16 is carried rigidly secured at one end of aswingable arm 1S having its other end mounted at a pivot point 20.Suitable means (not shown) is provided for swinging the arm 18 back andforth, thereby to oscillate the die 16 through a circular arc ofapproximately centered on the pivot point 20. Of course, the 0scillatorymovement of the die 16 must be synchronized with the reciprocatorymovement of the die 1i). In this manner, the die 16 is moved to itsposition registering with the die 10, whereupon these dies cooperate tocompress between them the wet pulp preform which was de-A p csited onthe die li during its immersion in the vat 12. This compression actionassists in completing the molding of the pulp article, and at the sametime more excess moisture is expressed therefrom. Following this corn? AY Y 3 pression action the pulp article is transferred from the die tothe die 16. This may be accomplished by a blowing or a sucking actionQThe suction which has been applied to the die 10 is shut oli, andsuction is then applied to the ldie 16. A flexible hose 22 connects thedie 16.to Athe .previously mentioned source .of suction, Vand suitableautomatic controls for the suction are synchronized with the movement ofthe two dies.- l

At the other eXtreme limit of its oscillatory movement, the die 16overhangs an end portion of an endless, horizontally disposed conveyorbelt 26, arranged to carry the molded pulp articles toward nal dryingand nishing apparatus (not shown). This end of the conveyor belt 26 ishorizontally,reciprocable, so that it may be shifted out of the way ofthe die 16'when this die is being Aoscillated through its arcuate pathtoward the die 10. The reciprocatory movement of this end of the belt 26.enables it to be positioned beneath the die 16 in the proper positionto receive a molded pulp article therefrom, as illustrated in Fig. 1. Itshould'be observed at thisrtime that the die 16 becomes completelyinverted as the result of its oscillatory motion through the 180 arcinmoving away from the die 10, so that the pulp article lands on its datbottom side as it drops onto the A belt 26 when the suction on the die16 is stopped. Furthermore, when the belt 26 is in its receivingposition beneath the die 16, it is spaced relatively closely thereto,

so that the pulparticle falls only a short distance from ,the die to thebelt, thereby avoiding damage to the article whilesit isV stillsomewhatmoist and hence is still quite pliable and fragile. Under somecircumstances, it may be desirable to applyV a blast of Vcompressed airthrough the `hose 22 to blow the pulp article from the die 16 Vonto thebelt 26.

, jHorizontal reciprocation ofthe end of the belt 26 may `beaccomplished by advancing the belt around a Xed pulley 27 and thencearound a pair of horizontally shiftable pulleys 28 and 29, therebyforming a pair of parallel loops 30and 32 in the belt 26. By shiftingthe pulleys 28 and 29 in unison between their positions shown inY Fig.'1 and their positions shown in Fig. 2, the loop 32 isreciprocatedrbetween its receiving position beneath the die 16 and itsclearing position out of the path of this die, While the loop 30provides the necessary adjustment of the slack to allow this movement ofthe belt 26. It is vevident that suitable automatic controls may beprovided for shifting the end of the belt 26 in proper synchronizationwith the movement of the die 16. Y f

TheY second embodiment of the invention illustrated in Figs. 3 and 4 isgenerally Vsimilar to that of the abovedescribed rst embodiment, but inthe second embodiment an arrangement is provided for shortening the pathtraveled by the transfer die, and the adjacent end of the conveyor beltmay be shifted in a diierent manner. A molding die 110 having a formingface 111 is vertically reciprocable into and out of a vat 112 containingpulp slurry.v4 The die 110 is mounted on the lower end Yof a hollowvertical shaft 114, which may be reciprocated vertically by 'anysuitable means to move the die V110 between an immersed moldingposition, shown in Fig. 3,

and an elevated compressing position, depicted in Fig., 4.

As, in the case'of the iirst described embodiment of the Iinvention, thedie 110 is reciprocated in a perfectly straight line motion, withouttilting or turning, and while held with its forming face 111 facing itsimmersed position at all times. Y

VA cooperating compression and transfer `die 116 is priovlded with aforaminous face 117 designed to mate with tl1e forming face 111v of thedier110. The die 116 is oscillated into mating registration with the die110, when this die is inits elevated position, by means of anoscillating mechanism including a swingable arm 118 having one endthereof secured at a pivot point V120. The Vdie 116 is also providedwith a pair of rigid parallel arms 1.2717, 0f Which Only one appears inthe drawings, Vfor securing this die pivotally to the other end of theswingable arm 118. A flexible hose 122 connects the die 116 to a sourceof suction, in the same manner as the hose 22 described in the tirstembodiment of the invention. A pair of cam rollers 123, of which onlyone is shown in Figs. 3 and 4, mounted,k on opposite sides of the die116 ride in an arcuate cam track designed to turn the die 116 about itstransverse axis during its oscillatory movement. The cam rollers 123serve as a pivot point for this turning motion, and the die 116 becomescompletely inverted as it swings between the extreme limits of itsoscillatory motion. It should be noted that the forming face 117 of thedie 116 is disposedY horizontally at both of the extreme limits of itsswing. During its inversion, the die 116 travels through a circular arcof more than 90 but of considerably less than 180 with respect to thepivot point 120, due to its simultaneous turning about the pivot pointprovided by the cam rollers 123. This mechanical movement advantageouslyfacilitates a more compact arrangement of the entire pulp moldingmachine.

An adjacent end portion of an endless conveyor belt 126 is disposedhorizontally and arranged to receive molded pulp articles, dropped orblown from the die 116, to carry these articles to the final drying andnishing apparatus. Y Thisend of the belt 126 passes around a movablepulley Y127 and over a pair of superposed fixed pulleys 12S and 129,thereby forming a swingable end loop 130 in the belt 126. By swingingthe pulley 127 through a short circular arc centered on the pulley 129,the loop 130 may be shifted back and forth between its horizontalposition aligned with the rest of the belt 126, shown in Fig. 3, and itsinclined position, shown in Fig. 4, wherein it has been dropped awayfrom the path of the die 116. By this arrangement the successivelyproduced molded pulp articles fall only a `short distance from the die116 to the belt 126.Y

It is evident that the two systems described in the two embodiments fortemporarily moving VVthe adjacent end of the conveyor belt out of thepath of t-he transfer die are interchangeable, and that -any othersuitable system may be employed for this purpose. For example, insteadof having a shiftable end portion for a relatively stationary conveyorbelt as herein described, an entirely separate shiftable table orconveyor could be employed conjunction with an entirely relativelystationary conveyor belt. Furthermore, other types of transfermechanisms, such as chutes, roller conveyors, and the like, maysometimesV be substituted for the endless belt conveyor describedherein.

Although the invention has been illustrated and described withparticular reference to only a single pair of cooperating dies, it is tobe understood that each of these dies may be of the multiple type. Thatis, a plurality of individual dies may be mounted side by side formovement as a group on a single die platen.

It will be obvious to those skilled in the art that various changes maybe made without departing Yfrom the spirit of the invention andtherefore the invention is not limited to what is shown in the drawingsand described in the specification, but only as indicated in theappended claims.

What is claimed is.:

. 1. Vliulp molding'apparatus, comprising a molding die having aforaminous forming face designed to form pulp articles by deposition ofpulp. fibers from a slurry thereof, means for vertically reciprocatingthe die in a straight line between a molding position immersed in pulpslurry and a compressing position elevated above the slurry, saidforming face of the die'being disposed horizontally and'held facingdownwardly toward its immersed position vduring itsV entirerecprocatorymovement, an oscillative and invertible transfer die mounted adjacent tothe compressing positionof the molding die, said transfer dieV having aface designed to mate with the forming face of the molding die, andmeansfor Yoscillating the transfer die and inverting it as it moves in acircular arc between a discharge position spaced `away from the moldingdie and a compressing position in which it is in mating registrationwith the molding die, said transfer die becoming completely inverted asit oscillates.

2. Pulp molding apparatus comprising a single molding die having aforaminous forming face designed to form pulp articles by deposition ofpulp fibers from a slurry thereof, means for vertically reciprocatingthe die in a straight yline between a molding position immersed in pulpslurry and a compressing position elevated above the slurry, saidforming face of the die being disposed horizontally and held facingdownwardly toward its immersed position during its entire reciprocatorymovement, a single oscillative and invertible transfer die having a facedesigned to mate with the forming face of the molding die, `and .anoscillating mechanism including a swingable arm having one end mountedat a pivot point `and joined at its other end to the transfer die forosc-illating the transfer die in a circular arc centered on said -pivotpoint, said transfer die becoming completely inverted as it oscillatesbetween a discharge position overhanging a discharge conveyor and acompressing position in which it is in mating registration with themolding die when the molding die is elevated.

3. The apparatus defined by claim 2 in which the transfer die is rigidlyjoined to said other end of said swingable arm, and the die oscillatesthrough a circular arc of approximately 180 centered on the pivot pointat said one end about which the other end of the swingable arm ismounted.

4. Pulp molding apparatus comprising a molding die having a foraminousforming face designed to form pulp articles by deposition of pulp fibersfrom a slurry thereof, means for vertically reciprocating the die in asubstantially straight line between a molding position immersed in pulpslurry and a compression position elevated above the slurry, saidforming face of the die being disposed horizontally and held facingdownwardly toward its immersed molding position during its entirereciprocatory movement, a transfer die mounted oscillatively andinvertibly adjacent to the elevated compressing portion of the moldingdie, an oscillating mechanism including an arm swingable about a pivotpoint at one end thereof land joined pivotally at its other end to thetransfer die whereby the arm oscillates the transfer die in a circulararc centered on said pivot point between a discharge position spacedaway from the molding die and a compressing position in which it is inmating registration with the molding die, and means for turning thetransfer die as it is oscillated by the arm to invert said diecompletely as it oscillates through considerably less than 180 of thecircular arc.

5. The apparatus defined by claim 4 in which the turning means includesa pair of cam rollers mounted on opposite sides of the transfer die, anda pair of arcuate 5 cam tracks cooperate with said rollers to invertsaid die completely as it oscillates through considerably less thanofthe circular arc.

6, Pulp molding apparatus comprising a molding die having a foraminousforming face designed to form pulp articles by deposition of pulp fibersfrom a slurry thereof, means for vertically reciprocating the die in asubstantially straight line between a molding position immersed in pulpslurry and a compressing position elevated above the slurry, saidforming face of the die being held disposed horizontally facingdownwardly toward its immersed molding position during its entirereciprocatory movement, a transfer die mounted oscillatively andinvertibly adjacent to the elevated compressing position of the moldingdie, an oscillating arm joined at one end thereof to the transfer dieand swingable about a fixed pivot point at the other end of the arm foroscillating the transfer die in a circular arc centered on said pivotpoint between a compressing position wherein it is in matingregistration with the rno-lding die and a discharge position spaced awayfrom the molding die, said transfer die being disposed horizontally atopposite limits of its oscillating movement in its compression positionand in its discharge position, and an endless movable belt dischargeconveyor disposed generally horizontally adjacent to the dischargeposition of the transfer die, the adjacent end portion of the conveyorbeing movable between a receiving position directly beneath and spacedclosely to the transfer die when the die is in its discharge positionand a clearance position wherein the movable end of the conveyor allowsclearance for the oscillating movement of said die.

7. The apparatus defined by claim 6 in which the movable end portion ofthe horizontal endless movable belt discharge conveyor is shiftablehorizontally between its receiving position and its clearance position.

8. The apparatus defined by claim 6 in which the movable end portion ofthe horizontal endless movable belt discharge conveyor is mountedpivotally for swinging movement downwardly to its clearance position andupwardly to its receiving position, said end portion being in alignmentwith the main portion of the conveyor when said end is in its receivingposition.

References Cited in the file of this patent UNITED STATES PATENTS1,158,634 Chaplin Nov. 2, 1915 1,203,197 Hogue Oct. 31, 1916 1,397,375Grunwald Nov. 15, 1921 1,880,458 Morris Oct. 4, 1932 2,225,134 SkolnikDec. 17, 1940 2,628,540 Randall Feb. 17, 1953 FOREIGN PATENTS 655,944Great Britain Aug. 8, 1951

